Power transmission belt

Abstract

A power transmission belt (10,21) of improved manufacture wherein a novel reinforcing fabric (4,14) is provided in the inner portion of the compression section (3,13) of the belt. The fabric is formed of yarns (20) having a low coefficient of thermal contraction and a high bias elongation to break. The yarns are formed of a mixture of natural and synthetic resin fibers and are subjected to heat treatment to effect the improved low coefficient of thermal contraction and high bias elongation to break.

We claim: 
     
       1. In a power transmission belt having an inner compression section, an outer tension section, and longitudinal tensile cords intermediate said compression and tension sections, the improvement comprising at least one layer of low thermal contraction fabric forming an inner portion of the compression section, said fabric being comprised of yarns formed of a mixture of natural and synthetic fibers in the ratio of approximately 30% to 70%, said yarns having a coefficient of thermal contraction of no more than approximately 1% and a bias elongation to break of greater than 60%.   
     
     
       2. The power transmission belt of claim 1 wherein said natural fibers comprise cotton. 
     
     
       3. The power transmission belt of claim 1 wherein said synthetic fibers comprise nylon fibers. 
     
     
       4. The power transmission belt of claim 1 wherein said synthetic fibers comprise polyester resin fibers. 
     
     
       5. The power transmission belt of claim 1 wherein said natural and synthetic fibers are blended in said yarns. 
     
     
       6. The power transmission belt of claim 1 wherein said natural and synthetic fibers are twist-mixed in said yarns. 
     
     
       7. The power transmission belt of claim 1 wherein said fabric is a plain weave fabric. 
     
     
       8. The power transmission belt of claim 1 wherein said fabric is bias laid in said layer. 
     
     
       9. The power transmission belt of claim 1 wherein said fabric comprises a wide angle fabric wherein the warp and woof yarns are disposed at an angle to each other of approximately 95° to 150°. 
     
     
       10. The power transmission belt of claim 1 wherein said fabric is rubber-coated. 
     
     
       11. The power transmission belt of claim 1 wherein said compression section is provided with short transverse reinforcing fibers intermediate said tensile cords and said layer. 
     
     
       12. The power transmission belt of claim 1 wherein said tension section is provided with short transverse reinforcing fibers. 
     
     
       13. The power transmission belt of claim 1 wherein said tension section is provided with at least one fabric layer at its outer surface. 
     
     
       14. The power transmission belt of claim 1 wherein said tensile section is provided with at least one stretchable fabric layer at its outer surface. 
     
     
       15. The power transmission belt of claim 1 wherein said compression section is provided with at least one longitudinal notch to define a multiribbed belt. 
     
     
       16. The power transmission belt of claim 1 wherein said belt defines a V-belt. 
     
     
       17. In a power transmission belt having an inner compression section, an outer tension section, and longitudinal tensile cords, the improvement comprising at least one layer of low thermal contraction fabric forming an inner portion of the compression section, said fabric being comprised of yarns formed of a mixture of natural and synthetic fibers in the ratio of approximately 30% to 70%, said yarns having a coefficient of thermal contraction of no more than approximately 1%.   
     
     
       18. The power transmission belt of claim 17 wherein said natural fibers comprise cotton. 
     
     
       19. The power transmission belt of claim 17 wherein said synthetic fibers comprise nylon fibers. 
     
     
       20. The power transmission belt of claim 17 wherein said synthetic fibers comprise polyester resin fibers. 
     
     
       21. The power transmission belt of claim 17 wherein said natural and synthetic fibers are blended in said yarns. 
     
     
       22. The power transmission belt of claim 17 wherein said natural and synthetic fibers are twist-mixed in said yarns. 
     
     
       23. The power transmission belt of claim 17 wherein said fabric is a plain weave fabric. 
     
     
       24. The power transmission belt of claim 17 wherein said fabric is bias laid in said layer. 
     
     
       25. The power transmission belt of claim 17 wherein said fabric comprises a wide angle fabric wherein the warp and woof yarns are disposed at an angle to each other of approximately 95° to 150°. 
     
     
       26. The power transmission belt of claim 17 wherein said fabric is rubber-coated. 
     
     
       27. The power transmission belt of claim 17 wherein said compression section is provided with short transverse reinforcing fibers intermediate said tensile cords and said layer. 
     
     
       28. The power transmission belt of claim 17 wherein said tension section is provided with short transverse reinforcing fibers. 
     
     
       29. The power transmission belt of claim 17 wherein said tension section is provided with at least one fabric layer at its outer surface. 
     
     
       30. The power transmission belt of claim 17 wherein said tensile section is provided with at least one stretchable fabric layer at its outer surface. 
     
     
       31. The power transmission belt of claim 17 wherein said compression section is provided with at least one longitudinal notch to define a multiribbed belt. 
     
     
       32. The power transmission belt of claim 17 wherein said belt defines a V-belt.